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Overview

The TTreePageNavigator component provides navigation controls for multi-page tree diagrams. It includes buttons for moving between pages and support for printing page ranges.

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Components

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TTreePageNavigator

Navigation control for tree pages. 
type
  TTreePageNavigator = class(TCustomTeeNavigator)
  published
    property Tree:TCustomTree;
    property OnButtonClicked;
    
    procedure EnableButtons; override;
    procedure Print; override;
    procedure PrintPages(FromPage, ToPage: Integer);
  end;
Properties:
  • Tree - The tree component to navigate
  • OnButtonClicked - Event fired when a button is clicked
The navigator includes the following buttons:
  • nbFirst - Go to first page
  • nbPrior - Go to previous page
  • nbNext - Go to next page
  • nbLast - Go to last page

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Usage Examples

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Basic Setup

var
  Navigator: TTreePageNavigator;
begin
  Navigator := TTreePageNavigator.Create(Self);
  Navigator.Parent := Panel1;
  Navigator.Tree := Tree1;
  Navigator.Align := alBottom;
end;

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Design-Time Setup

// Drop TTreePageNavigator on form
// Set properties:
TreePageNavigator1.Tree := Tree1;
TreePageNavigator1.Align := alBottom;

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Enable/Disable Buttons

procedure TForm1.UpdateNavigator;
begin
  TreePageNavigator1.EnableButtons;
  
  // Buttons are automatically enabled/disabled based on:
  // - First/Prior disabled when on first page
  // - Next/Last disabled when on last page
  // - All disabled when Tree.Page.Count = 0
end;

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Print Current Page

procedure TForm1.PrintCurrentPage;
begin
  Tree1.Print;
end;

procedure TForm1.PrintAllPages;
begin
  TreePageNavigator1.Print;  // Shows print dialog
end;

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Print Page Range

procedure TForm1.PrintRange;
begin
  // Print pages 1 through 5
  TreePageNavigator1.PrintPages(1, 5);
end;

uses TreeNavigator;

procedure TForm1.ShowPrintDialog;
var
  PrintDlg: TPrintDialog;
begin
  PrintDlg := TreePrintDialog(Tree1);
  try
    if PrintDlg.Execute then
    begin
      TreePageNavigator1.PrintPages(
        PrintDlg.FromPage, 
        PrintDlg.ToPage
      );
    end;
  finally
    PrintDlg.Free;
  end;
end;

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Handle Button Click Events

procedure TForm1.TreePageNavigator1ButtonClicked(
  Sender: TObject; 
  Button: TTeeNavigateBtn
);
begin
  case Button of
    nbFirst: ShowMessage('First page');
    nbPrior: ShowMessage('Previous page');
    nbNext:  ShowMessage('Next page');
    nbLast:  ShowMessage('Last page');
  end;
end;

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Manual Page Navigation

procedure TForm1.GoToPage(PageNum: Integer);
begin
  if (PageNum >= 1) and (PageNum <= Tree1.Page.Count) then
  begin
    Tree1.Page.Page := PageNum;
    TreePageNavigator1.EnableButtons;
  end;
end;

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Get Current Page

function TForm1.GetCurrentPage: Integer;
begin
  Result := Tree1.Page.Page;
end;

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Get Total Pages

function TForm1.GetTotalPages: Integer;
begin
  Result := Tree1.Page.Count;
end;

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Check if First/Last Page

function TForm1.IsFirstPage: Boolean;
begin
  Result := Tree1.Page.Page = 1;
end;

function TForm1.IsLastPage: Boolean;
begin
  Result := Tree1.Page.Page = Tree1.Page.Count;
end;

procedure TForm1.NavigateFirst;
begin
  if Tree1.Page.Page > 1 then
  begin
    Tree1.Page.Page := 1;
    TreePageNavigator1.EnableButtons;
  end;
end;

procedure TForm1.NavigatePrior;
begin
  if Tree1.Page.Page > 1 then
  begin
    Tree1.Page.Page := Tree1.Page.Page - 1;
    TreePageNavigator1.EnableButtons;
  end;
end;

procedure TForm1.NavigateNext;
begin
  if Tree1.Page.Page < Tree1.Page.Count then
  begin
    Tree1.Page.Page := Tree1.Page.Page + 1;
    TreePageNavigator1.EnableButtons;
  end;
end;

procedure TForm1.NavigateLast;
begin
  if Tree1.Page.Page < Tree1.Page.Count then
  begin
    Tree1.Page.Page := Tree1.Page.Count;
    TreePageNavigator1.EnableButtons;
  end;
end;

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Custom Print Title

procedure TForm1.PrintWithTitle;
begin
  TreePageNavigator1.Name := 'Organization Chart';
  TreePageNavigator1.Print;
  // Printer.Title will be set to 'Organization Chart'
end;

uses TreeNavigator;

procedure TForm1.PrintMultipleCopies;
var
  PrintDlg: TPrintDialog;
  i: Integer;
begin
  PrintDlg := TreePrintDialog(Tree1);
  try
    if PrintDlg.Execute then
    begin
      for i := 1 to PrintDlg.Copies do
        TreePageNavigator1.PrintPages(
          PrintDlg.FromPage, 
          PrintDlg.ToPage
        );
    end;
  finally
    PrintDlg.Free;
  end;
end;

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Update After Page Change

procedure TForm1.Tree1AfterDraw(Sender: TObject);
begin
  // Update navigator buttons after drawing
  TreePageNavigator1.EnableButtons;
  
  // Update status bar
  StatusBar1.SimpleText := Format('Page %d of %d', 
    [Tree1.Page.Page, Tree1.Page.Count]);
end;

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Combined with Page Controls

procedure TForm1.SetupPageNavigation;
begin
  // Set up tree pages
  Tree1.Page.Count := 5;
  Tree1.Page.Page := 1;
  
  // Setup navigator
  TreePageNavigator1.Tree := Tree1;
  TreePageNavigator1.EnableButtons;
  
  // Update display
  Label1.Caption := Format('Page %d of %d', 
    [Tree1.Page.Page, Tree1.Page.Count]);
end;

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Keyboard Navigation

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; 
  Shift: TShiftState);
begin
  case Key of
    VK_HOME:  NavigateFirst;
    VK_PRIOR: NavigatePrior;
    VK_NEXT:  NavigateNext;
    VK_END:   NavigateLast;
  end;
end;

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Helper Functions

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TreePrintDialog

Creates a print dialog configured for tree page printing. 
Function TreePrintDialog(const Tree:TCustomTree):TPrintDialog;
Features:
  • Automatically configured for page range printing
  • MinPage set to 1
  • MaxPage set to Tree.Page.Count
  • Options include page number selection
  • PrintRange set to prPageNums
Usage: 
var
  PrintDlg: TPrintDialog;
begin
  PrintDlg := TreePrintDialog(Tree1);
  try
    if PrintDlg.Execute then
    begin
      // User selected print settings
      // PrintDlg.FromPage and PrintDlg.ToPage contain range
      // PrintDlg.Copies contains number of copies
    end;
  finally
    PrintDlg.Free;
  end;
end;

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Standard Print

  • Prints all pages by default
  • Shows print dialog for user selection
  • Supports multiple copies
  • Respects page range selection

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PrintPages Method

  • Direct printing without dialog
  • Specify exact page range
  • FromPage: Starting page (1-based)
  • ToPage: Ending page (0 = all pages)
  • Printer title from Navigator.Name
  • Automatic page breaks
  • Uses Tree.ChartPrintRect for layout
  • Maintains page state after printing

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Events

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OnButtonClicked

Fired when any navigator button is clicked. 
property OnButtonClicked: TTeeNavigatorButtonClickEvent;

procedure TForm1.TreePageNavigator1ButtonClicked(
  Sender: TObject;
  Button: TTeeNavigateBtn
);
begin
  // Handle button click
end;

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Button States

Buttons are automatically enabled/disabled:
  • First/Prior buttons:
    • Enabled when Tree.Page.Page > 1
    • Disabled on first page
  • Next/Last buttons:
    • Enabled when Tree.Page.Page < Tree.Page.Count
    • Disabled on last page
  • All buttons:
    • Disabled when Tree.Page.Count = 0
    • Disabled when Tree is nil

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See Also

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